Electric switch



Patented Mar. 13, 1934 UNITED STATES- PATENT OFFICE ELECTRIC SWITCH Continuation of application Serial No. 275,076, May 4, 1928. This application November 8,

1931, Serial No. 573,483

15 Claims.

This invention relates to electric switches and more particularly to a switch unit adapted to be placed in a street surface and actuated by the passage of vehicles.

This application is a continuation of application Serial No. 275,076, filed May 4, 1928.

The object of this invention is to provide a pressure-operated switch unit in the form of a yieldable waterproof package.

Another object of the invention is to provide a switch unit of the character designated in which the number of moving parts shall be reduced to a minimum.

A further object of the invention is to provide a pressure-operated switch unit adapted to be placed in a roadway so that it shall not be affected by moisture or temperature conditions.

A further object of the invention is to provide a switch unit of the character designated which [0 shall be simple in operation, rugged in construction and more efficient than similar apparatus heretofore employed.

These and other objects of the invention will be more manifest from the following specification g5 and drawing and specifically set forth in the appended claims.

In the drawing:

Figure 1 is a perspective view of a switch package embodying our invention;

Figure 2 is a fragmentary view of the switch shown in Figure 1, showing the relation of the several parts;

Figure 3 is a sectional view of a switch placed in a roadway; and

Figure 4 is a perspective view of the casing in which the switch is housed.

Referring to the drawing, there is shown in Figures 1 and 2 a switch unit embodying our invention, in which the electrical contact members employed are enclosed in a watertight package 10, and this package is housed in a rigid boxlike casing 11 shown in Figure 4, wherein it is protected from the rough usage to which it may be subjected.

The switch unit comprises two superposed metallic contact members 12 and 13 constructed of such resilient material that they may readily yield and make contact when any appreciable pressure is exerted upon them. These members are in the form of thin metallic sheets or strips which are good conductors of electricity. These conductors may be steel, for example, and are provided with wires 14 and 15, respectively, which serve as connectors for the switch.

The conductors 12 and 13 are spaced apart by a member 16 of resilient non-conducting material and may extend between all of the peripheral plate edges as shown. This spacing member is shown as a single piece of material, such as sponge rubber and the like, but it is obvious that it may be divided into separate members and placed along the edges to serve the same purpose. The spacer member 16 is secured to the peripheral edges of the sheets so as to assist in holding them in operable relation and to minimize any tendency of distortion due to the heavy strains imposed thereon. The spaced conductors thus assembled are enclosed in a suitable protective covering of flexible material. As shown, this casing or envelope may take the form of a heavy fabric covering 17 which is wrapped or otherwise fitted closely over the parts so as to assist in holding them in the desired fixed relation and form a flexible package. To insure the package against moisture and make it watertight so as to prevent corrosion or other deleterious effects which may result from exposure, the unit is then enclosed by a rubber casing 18. This casing may be rendered watertight in any suitable manner, as, for example, by vulcanizing or cementing the covering together. After the application of the rubber casing, the unit is then wrapped in another covering of heavy fabric 19, such as friction tape.

The switch contact elements thus assembled in the form of a watertight package, the unit may have application to a wide variety of uses and especially where the switch is exposed to rough usage, moisture and weather conditions. In order to adapt the switch for use in a roadway where it is subjected to the extreme conditions imposed by heavy vehicular traffic the package may be placed in a rigid hollow metal casing 11, which is Open at the top. The top of the casing 11 is closed by a yieldable cover or pad 20, which is held in place by cleats 21 and tap bolts 22. Associated with the cleats are wedge-shaped members 23 and 24 for adjusting the tension of the cover 20 as hereinafter described. This cover maybe of any suitable yieldable material such as heavy tread rubber adapted to withstand the severe shocks imposed upon it by heavy vehicles. When it is necessary for any reason to regulate the pressure required to operate the contact sheets 12 and 13, the wedge members 23 and 24 may be employed to place a greater stress upon the tread member so that it may respond more readily to the pressure to which it may be subjected.

The box for enclosing and protecting the switch is preferably of cast steel metal and is provided 110 with support plates 26 which form additional means for holding the box in the roadway in which it is placed as shown in Figure 3. In assembling the roadway contact device, the package 10 is fitted into the box 11 and firmly secured to the bottom and sides thereof by a suitable cement 25 to prevent relative shifting of the parts. To further provide for any displacement or deformation of the switch elements, the package is adapted to fit snugly within the inside walls 28 of the box. The top portion on the inside walls of the box are provided with a peripheral ledge or step 29 adapted to receive and support the edges of the tread covering 20 which completely fills the box. By providing this ledge, the edges of the box receive the impact of the vehicle wheel and the shock on the cover and switch members is reduced to a minimum.

In assembling the unit, the tread covering 20 is also cemented to the top of the package 10 and to the ledges of the box by a similar cement 25. While we have shown the cover or pad 20 secured to the package 10 by a cement, it is also contemplated to form the cover pad and package together as an integral part before the covering and package are placed in the metal box. This is accomplished by vulcanizing the cover 20 and package 10 together so that any possibility of the cover and package becoming separated through severe usage is reduced to a minimum.

The above construction provides an electric switch which is particularly adapted for use as a vehicle actuated control in highway signal systems wherein a switch member is placed in a roadway surface and adapted to be actuated by the passage of vehicles. A switch construction such as that described and forming the subject matter of our invention is readily able to with stand the severe stress imposed upon it by heavy vehicular traffic, and is waterproof so that it may not be affected by adverse weather conditions.

This is another important feature of our invention, as it is desirable that the electric contactor members shall be maintained free from moisture to insure the desired positive operation of these parts. It will also be seen that by placing the box 11 in the roadway with its edges flush with the surface thereof and securing the edges of the yieldable cover to the walls of the box, there is provided a protective structure between the roadway surface and the yieldable member which transmits movement to the contactor members located therein.

Having thus described our invention, it is obvious that various changes and modifications may be made therein without departing from the scope of the invention, as set forth in the appended claims.

Having described our invention. what we claim as new and desire to secure by Letters Patent is:

1. A circuit closer package including. in combination. a pair of spaced. superposed contactor sheets of resilient material. compressible insulating material separating the peripheries of said sheets, a fabric covering for said assembly and a flexible vulcanized casing enclosing said covering.

2. A vehicle operated circuit closer package including. in combination, facing sheets of resilient conducting material, insulating material peripherally spacing said plates. a protective covering enclosing the sheets and insulation material and an enclosing resilient, waterproof casing for said plate assembly.

3. A vehicle operated circuit closer including. in combination, a rigid receptacle open at the top and adapted to be sunk in the paving material of a highway with the upper edges thereof substan tially flush with the surface of said highway, a waterproof package including spaced resilient contactor members in said receptacle and a flexible pad in said receptacle covering said package and having its upper surface substantially flush with the upper. edges of said receptacle whereby contact members shall be operated by a vehicle.

4. In a vehicle operated contactor, the combination of a circuit closer enclosed in a waterproof package, a receptacle of rigid material open at the top andadapted'to be sunk with its upper edges substantially flush with a highway surface, a compartment in said receptacle for said circuit closer package, a flexible, resilient pad covering said package and completely filling said receptacle to the upper edges thereof and means included in said receptacle for supporting said pad.

5. In a vehicle operated contactor, the combination of a circuit closer enclosed in a waterproof package. a receptacle of rigid material open at the top and adapted to be sunk with its upper edges substantially flush with a highway surface, a compartment in said receptacle for said circuit closer package, a flexible, resilient pad covering said package and completely filling said receptacle to the upper edges thereof, means in said receptacle to support the periphery of said pad, and means associated with said pad for effecting a sensitive action thereof on said contactor package.

6. A container for a vehicle operated contactor package including a receptacle of rigid material open at the top and adapted to be sunk with its upper edges substantially flush with a highway surface, a compartment in said receptacle for said contactor package, a flexible, resilient pad covering said package and completely filling said receptacle to the upper edges thereof, means on said receptacle to support the periphery of said pad. a wedge between a wall of said receptacle and an edge of said pad for increasing the sensitive action of said pad and means attaching said wedge to said receptacle. said means serving to adjust said wedge to regulate the lateral pressure on said pad.

'7. A pressure operated contactor sunk in a highway and including spaced, substantially parallel plates of spring metal, a resilient flexible pad covering said plates, and means for effecting a sensitive action of said pad.

8. As a new article of manufacture, a pressure operated circuit closer comprising a pair of yieldable contactor members, yieldable insulation members for normally spacing the contact members apart. a protective covering for said contactor members and a yieldable vulcanized rubber casing for sealing the protective covering and the enclosed members against the ingress of moisture.

9. As a new article of manufacture, a pressure operated roadway switch for opening and closing an electric circuit comprising a substantially fiat cast metal base, a fabric covering for enclosing the conductor members and a vulcanized rubber casing formed over the fabric covering.

10. As a new article of manufacture, a pressure operated roadway switch for opening and closing an electric circuit comprising a substantially flat cast metal base. a fabric covering for enclosing the conductor members, a vulcanized rubber casing formed over the fabric covering and an adhesive cement filling between said casing and the edges of said base.

11. As a new article of manufacture, a pressure operated roadway switch for opening and closing an electric circuit comprising a substantially flat rectangular base having a recess formed in the top surface thereof, yieldable conductor members located in said recess and insulated from each other, a yieldable waterproof casing enclosing the contact members and substantially filling the recess and a yieldable, cover secured to the peripheral edges of said recess for transmitting pressure to operate said conductor members.

12. As a new article of manufacture, a pressure operated roadway switch for opening and closing an electric circuit comprising a substantially flat rectangular base having a recess formed in the top surface thereof, yieldable conductor members located in said recess and insulated from each other, a yieldable waterproof casing enclosing the contact members and substantially filling the recess, a yieldable cover for the recess and means for clamping the peripheral edges of the cover to the top edges of said recess.

13. A switch including-a circuit closing unit comprising a pair of flat plates, at least one of said plates being formed of resilient material, yieldable separators interposed between portions only of said plates to normally maintain the latter out of electrical contact, an envelope for said unit and distinct from said separators, a cover arranged above said envelope and presenting a substantially fiat upper surface, and leads extending from said plates.

14. A switch including a circuit closing unit comprising a pair of flat plates of relatively great breadth means for maintaining said plates in normally spaced relationship, at least one of said plates being formed of resilient material, means providing an envelope for said circuit closing unit, and leads extending from said plates.

15. An electrical switch including a circuit closing unit comprising a pair of spaced contacts, one of said contacts being of a resilient character, an envelope for said unit, a base formed with a recess accommodating such envelope and unit, and said recess being enlarged above the body of said envelope, a cover member within said enlargement and the upper face of said cover extending into substantially the same plane as the upper edges of said base.

CHARLES D. GEER. EUGENE D. S'I'IRLEN. 

